1. Field of the Invention
The present invention relates to orthodontic appliances, and more particularly, to hybrid orthodontic appliances with improved rigidity and structure for controlling the position of a patient's teeth.
2. Description of the Related Art
Removable orthodontic appliances are well known in the art for use before, during and after orthodontic treatment, for the purpose of moving and retaining the positions of an orthodontic patient's teeth. The appliances are removable and worn by patients in accordance with instructions from an orthodontist.
Removable orthodontic appliances may be constructed for use on both upper and lower dental arches and have typically been formed using variations of one of two methods.
A first method utilizes a combination of steel wire, springs, expansion screws and orthodontic acrylic. A wire framework for tooth alignment is placed along the labial and sometimes lingual areas of the dental arch. Orthodontic acrylic is applied to the palate to unite the wire frameworks and provide a secure foundation for controlled tooth-movement or retention. One common example of such an appliance is known as the Hawly retainer. This appliance has many functions and modifications due to its rigidity and structure. However, this appliance includes a wire that is visible across the front of a patient's teeth, which is adjusted periodically.
The second method utilizes thermal material. The thermal material is heated and then vacuum formed to a model of the patient's teeth. The invisible retainer encases the patient's teeth. This appliance is preferably transparent, but it lacks rigidity and structure, and is thereby flexible and easily cracked and broken. Invisible orthodontic appliances have been utilized in the orthodontic industry for at least the last 25 years. The primary function of the invisible retainer is to retain the position of the teeth following orthodontic treatment, or to allow for minor tooth movement using a series of these retainers.
A need exists for an appliance that combines the advantages of the two previous techniques, while at the same time eliminating the disadvantages of both.